Biocompatibility and thermodynamic properties of PEGDA and two of its copolymer.

During the last years substantial effort was taken in order to provide an effective and safe pharmacotherapy that can be adjusted to the individual needs of patients. Stereolithography is a simple and accurate additive manufacturing technology. According to these characteristics, it may offer unique opportunities for the industrial fabrication of structured drug delivery systems (DDS), which can be tailored to individual needs. During the stereolithographic process photopolymerizable biomaterial is transformed, layer by layer, into the designed polymer DDS. Combined with inkjet printing in an innovative 3D building system it enables selective and precise incorporation of the drug depot into the basic body of the DDS. Poly(ethylene glycol) diacrylate (PEGDA), a hydrophilic and low-immunogenic compound, is a suitable material as drug depot in a photopolymerizable basic biomaterial for this purpose. By combination of PEGDA with other acrylates, the physical properties of the DDS can be adjusted towards the desired characteristics. Therefore, it should be possible to modify the drug release profile through the positioning of drug depots and the diffusion of the drug and adjust it for a wide range of applications. In this study we investigated basic biological and thermodynamic properties of conventionally photocured systems consisting of PEGDA and its coacrylates: 1,3-butanediol diacrylate and pentaerythritol triacrylate. Our preliminary outcomes demonstrate the hydrophilic character of the samples and the importance of a rinsing process. They also show that the addition of different amounts of co-monomers influence the glass transition temperature, which increases with increasing content of coacrylate. Therefore, PEGDA/comonomer composition can be used as a tool for the modification of drug release properties. Consequently, these materials may be regarded as interesting and promising components for DDS via novel additive manufacturing with the ability of highly controlled drug release.

What about upwind buffer zones for aerial applications?

Buffer zones are areas set adjacent to areas sprayed with pesticides in which spray drift can deposit without consequence. It has been suggested that buffer zones should totally surround areas to be sprayed. We reviewed the scientific literature and employed a recently developed mechanistic model of spray drift to assess the magnitude of upwind spray drift and the consequent need for upwind buffer zones. Neither the scientific literature nor the AgDRIFT model support the need for upwind buffer zones for typical aerial spray applications.

An introduction to aerial spray modeling with FSCBG. Forest Service Cramer-Barry-Grim.

The FSCBG aerial spray drift and deposition model predicts the dispersion of material released from aircraft into the atmosphere, and particularly downwind from the release point. The effects of aircraft wake structure, droplet evaporation, local meteorology, penetration through forest or agricultural canopies, and prediction of ground or canopy deposition, air dosage, and concentration are all included in the model. The long developmental and validation history of the model, a brief summary of its assumptions and underlying approximations, and its present user-friendly operation on personal computers are reviewed and highlighted in this paper.

Chronic Nocardia asteroides endophthalmitis after extracapsular cataract extraction.

A 65-year-old man underwent an uncomplicated extracapsular cataract extraction with placement of a posterior chamber intraocular lens. The patient developed delayed-onset chronic endophthalmitis caused by Nocardia asteroides. This was confirmed on multiple intraocular cultures, as well as histopathologic examination of the lens capsular bag. The patient was treated with periocular, intravitreal, and systemic antibiotic treatment, combined with intraocular lens removal, total capsulectomy, and three vitrectomies in an attempt to eradicate the organism and calm the eye. The patient went on to develop widespread endophthalmitis that required enucleation of the infected globe. To our knowledge, this is the first case of delayed-onset chronic endophthalmitis caused by N asteroides after extracapsular cataract extraction with a posterior chamber intraocular lens.

Phacoemulsification combined with pars plana vitrectomy.

Phacoemulsification combined with pars plana vitrectomy was performed on seven patients with both cataracts and vitreoretinal disease. Six of the seven had a posterior chamber intraocular lens (PC-IOL) placed in the capsular bag following cataract extraction. Visual acuities ranging from light perception to hand movement preoperatively, postoperatively ranged from hand movement to 20/25. There were no perioperative complications. During an average follow-up of more than 6 months, neovascular glaucoma developed in one patient, and a conjunctival cyst in another. The PC-IOLs were well tolerated. The small limbal incision used in phacoemulsification allows better control during the vitrectomy procedure and ensures a water-tight wound. In addition, with the limbal approach, the posterior lens capsule is maintained, with all the attendant advantages.

Corneal-scleral melt in association with cataract surgery and intraocular lenses: a report of four cases.

Four patients with rheumatoid arthritis had cataract extraction with implantation of an intraocular lens (IOL). Postoperatively three patients developed progressive scleromalacia perforans. All three cases required patch grafting of the sclera and two of them developed progressive melting of the sclera and graft. The fourth case involved progressive corneal melting with extrusion of the IOL despite treatment with penetrating keratoplasties. All four cases developed retinal detachments with loss of vision and three of the eyes were subsequently enucleated. We describe each case and discuss the clinicopathologic correlations of this condition. The need for careful evaluation of rheumatoid arthritis patients with cataract surgery and IOL implantation is emphasized.

Retinal arterial macroaneurysms.

Retinal arterial macroaneurysms represent a distinct clinical entity. Macroaneurysms are seen in the elderly with a marked female predominance and a strong association with hypertension and arteriosclerotic vascular changes. The classic appearance provides an easy diagnosis; however, variable presentations, such as subretinal hemorrhage, macular exudate, and epiretinal membranes can make the diagnosis difficult. The differential diagnosis of retinal arterial macroaneurysms include retinal telangiectasia, angiomatosis retinae, venous macroaneurysms, background diabetic retinopathy, and cavernous hemangioma. The clinical characteristics of the reported cases are summarized, and our series of 60 patients is presented. The natural history of most macroaneurysms is spontaneous involution without loss of vision. However, visual loss may occur secondary to macular edema, exudate, hemorrhage and neurosensory retinal detachment, and photocoagulation may expedite visual recovery. Photocoagulation treatment may be applied directly to the macroaneurysm, indirectly by surrounding the macroaneurysm, or as a combination of these two methods.